Vaginal birth after cesarean.

Allowing a woman with a previous cesarean birth a trial of labor rather than performing an elective repeat cesarean section continues to be a controversial area in obstetrics today. In an effort to evaluate the risks associated with a trial of labor, a prospective investigation was undertaken from July 1, 1982, through June 30, 1984. During the first year of the study, patients with a known vertical scar or more than one prior cesarean birth were excluded from an attempted trial of labor. Beginning July 1, 1983, patients with two prior cesarean births were no longer excluded and were studied prospectively. During this 2-year period, 32,854 patients were delivered of their infants at the Los Angeles County/University of Southern California Medical Center. Of these patients, 2708 (8.2%) had undergone a prior cesarean birth, and 1796 women (66%) underwent a trial of labor. A total of 1465 (81%) of them achieved a vaginal delivery. Successful vaginal delivery by the number of prior cesarean sections was as follows: one, 82%; two, 72%; three, 90%. When contrasted with the group without a trial of labor, the group with a trial of labor had significantly less maternal morbidity. In a comparison of the groups with and without a trial of labor, the incidence of uterine dehiscence (1.9% versus 1.9%) and rupture (0.3% versus 0.5%) was similar. With the application of attempted vaginal delivery in our patients with a previous cesarean birth, we were able to reduce our cesarean delivery rate for this population alone by 54%. In summary, the benefits associated with a trial of labor in the patient with a prior cesarean birth far outweigh the risks. The policy of "once a cesarean section, always a cesarean section" should be abandoned.